package 蓝桥杯;

import java.util.Scanner;

public class digit2  {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a =sc.nextInt();
        int day=0;
        while (a>=1) {
            if (a!=1) {
                day++;
                a = a/2;
            }else{
                break;
            }
        }
        System.out.println(day);
    }
}
